Question:Just how long is 40 days according to the Bible.And why are there so many references to “Forty Days”.

Genesis 7:4Seven days from now I will send rain on the earth for fortydays and forty nights, and I will wipe from the face of the earth every living creature I have made."

Genesis 50

1 Joseph threw himself upon his father and wept over him and kissed him. 2 Then Joseph directed the physicians in his service to embalm his father Israel. So the physicians embalmed him, 3 taking a full forty days, for that was the time required for embalming. And the Egyptians mourned for him seventy days.

Exodus 34:28Moses was there with the LORD fortydays and forty nights without eating bread or drinking water. And he wrote on the tablets the words of the covenant—the Ten Commandments.

Numbers 13:23-2823 When they reached the Valley of Eshcol, [b] they cut off a branch bearing a single cluster of grapes. Two of them carried it on a pole between them, along with some pomegranates and figs. 24 That place was called the Valley of Eshcol because of the cluster of grapes the Israelites cut off there. 25 At the end of forty days they returned from exploring the land.

Report on the Exploration

26They came back to Moses and Aaron and the whole Israelite community at Kadesh in the Desert of Paran. There they reported to them and to the whole assembly and showed them the fruit of the land. 27 They gave Moses this account: "We went into the land to which you sent us, and it does flow with milk and honey! Here is its fruit. 28 But the people who live there are powerful, and the cities are fortified and very large.

Numbers 14:34For forty years—one year for each of the fortydays you explored the land—you will suffer for your sins and know what it is like to have me against you.'

1 Samuel 17:16For fortydays the Philistine came forward every morning and evening and took his stand.

1 Kings 19:8So he got up and ate and drank. Strengthened by that food, he traveled fortydays and forty nights until he reached Horeb, the mountain of God.

Jonah 3:4On the first day, Jonah started into the city. He proclaimed: "Forty more days and Nineveh will be overturned."

Mark 1:13and he was in the desert fortydays, being tempted by Satan. He was with the wild animals, and angels attended him.

Acts 1:3

3After his suffering, he showed himself to these men and gave many convincing proofs that he was alive. He appeared to them over a period of forty days and spoke about the kingdom of God.